Research by a medical student at the University of Miami Miller School of Medicine found that the more chocolate young men ate, the more acne they had. For example, men ages 18 to 35 that ate eight ounces of chocolate a day could see their number of pimples jump from fewer than four to as many as 70 in as little as seven days.

"The numbers speak for themselves," said researcher Samantha Block.

The study used pure chocolate which can contain ingredients with "pore-clogging properties" such as caffeine and theobromine.